1. Field of the Invention
The present invention relates to a transdermal patch, a preparation of a transdermal patch, and a use of the transdermal patch. In particular, the transdermal patch comprises buprenorphine as an active agent.
2. Description of Background Art
Buprenorphine is an endoethylene morphinan derivative and a partial agonist of μ-opioid receptors with a strong analgesic effect. For parenteral administration, the action of 0.3 mg of buprenorphine corresponds to the effect of 12 mg morphine. The duration of action is about 6-8 hours, which is about twice as long as comparable strong analgesics. Because of its dependence potential, buprenorphine should not be used to treat acute pain.
As a transdermal patch, sustained release buprenorphine is used especially for the treatment of moderate non-malignant pain in various potencies if an opioid to achieve adequate analgesia is necessary (e.g. Norspan® 5/10/20 micrograms/hour transdermal patch) or for the treatment of moderate to severe pain, such as that associated with cancer, and severe pain when there is insufficient efficacy with non-opioid analgesics (such as with Transtec PRO® 35/52.5/70 micrograms/hour transdermal patch) or for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment for which alternative treatment options are inadequate (e.g. Butrans® 5/10/15/20 micrograms/hour transdermal system).
Since these transdermal opioid patches are applied over a period of up to 7 days on the skin, transdermal therapeutic system (e.g., a patch) must enable consistent drug release over this period, must be comfortable to the wearer, and have sufficient adhesive force so that the matrix layer does not detach from the cover layer and the patch does not dissociate from the skin prematurely.
Transdermal patches comprising buprenorphine, which are already available on the market have a unidirectional cover layer of polyethylene terephthalate that faces away from the skin of the wearer (see EP 1009393 B1 and Norspan® 5/10/20 micrograms/h (manufactured by Gruenenthal) and Transtec PRO® 35/52.5/70 micrograms/h (manufactured by Gruenenthal)). However, there is still a need to improve the comfort of the patch and to provide a transdermal therapeutic system that has a sufficient adhesion of the drug-containing matrix during the storage period and in use.